12.1 – Experiments, Surveys, & Observational Studies

• Survey – data are from responses given by a sample and used to make a general conclusion about the population.

• Survey – data are from responses given by a sample and used to make a general conclusion about the population.

• Population – the group being studied

• Survey – data are from responses given by a sample and used to make a general conclusion about the population.

• Population – the group being studied• Census – a survey in which the entire

population is polled.

• Survey – data are from responses given by a sample and used to make a general conclusion about the population.

• Population – the group being studied• Census – a survey in which the entire

population is polled.• Sample – a smaller portion of the population

that is polled.

• Survey – data are from responses given by a sample and used to make a general conclusion about the population.

• Population – the group being studied• Census – a survey in which the entire

population is polled.• Sample – a smaller portion of the population

that is polled.• Biased (survey) – a survey in which the design

favors a certain outcome.

• Survey – data are from responses given by a sample and used to make a general conclusion about the population.

• Population – the group being studied• Census – a survey in which the entire population is

polled.• Sample – a smaller portion of the population that is

polled.• Biased (survey) – a survey in which the design favors

a certain outcome.• Unbiased (survey) – a survey in which the design is

not based on any predetermined characteristics of the population.

Ex. 1 State whether each survey would produce a random sample. Write yes or no and explain.

Ex. 1 State whether each survey would produce a random sample. Write yes or no and explain.

a) Asking every tenth person coming out of a theater how many times a week they go to the theater to determine how often city residents support the performing arts.

Ex. 1 State whether each survey would produce a random sample. Write yes or no and explain.

a) Asking every tenth person coming out of a theater how many times a week they go to the theater to determine how often city residents support the performing arts.

No, b/c those people may go to the theater more than the average person.

Ex. 1 State whether each survey would produce a random sample. Write yes or no and explain.

a) Asking every tenth person coming out of a theater how many times a week they go to the theater to determine how often city residents support the performing arts.

No, b/c those people may go to the theater more than the average person.

b) Surveying people going into a pet store to find out if the city’s residents support the building and maintaining of a dog park.

Ex. 1 State whether each survey would produce a random sample. Write yes or no and explain.

a) Asking every tenth person coming out of a theater how many times a week they go to the theater to determine how often city residents support the performing arts.

No, b/c those people may go to the theater more than the average person.

b) Surveying people going into a pet store to find out if the city’s residents support the building and maintaining of a dog park.

No, b/c those people may be more likely to support a dog park than the average person.

Ex. 1 State whether each survey would produce a random sample. Write yes or no and explain.

a) Asking every tenth person coming out of a theater how many times a week they go to the theater to determine how often city residents support the performing arts.No, b/c those people may go to the theater more than the

average person.

b) Surveying people going into a pet store to find out if the city’s residents support the building and maintaining of a dog park.No, b/c those people may be more likely to support a dog park

than the average person.

c) A box contains the name of every student in the school. A hundred names are randomly pulled out of the box. Those students are asked their opinions on the new cafeteria rules.

Ex. 1 State whether each survey would produce a random sample. Write yes or no and explain.

a) Asking every tenth person coming out of a theater how many times a week they go to the theater to determine how often city residents support the performing arts.No, b/c those people may go to the theater more than the average

person.

b) Surveying people going into a pet store to find out if the city’s residents support the building and maintaining of a dog park.No, b/c those people may be more likely to support a dog park than

the average person.

c) A box contains the name of every student in the school. A hundred names are randomly pulled out of the box. Those students are asked their opinions on the new cafeteria rules.Yes, b/c everyone as an equal chance of being selected.

Ex. 2 Chris wants to determine the most desired location for the senior class trip. Which questions will get him the answer he is seeking?

Ex. 2 Chris wants to determine the most desired location for the senior class trip. Which questions will get him the answer he is seeking?

a) Do you like Disneyland?

Ex. 2 Chris wants to determine the most desired location for the senior class trip. Which questions will get him the answer he is seeking?

a) Do you like Disneyland?

b) Which is better, King’s Island or Cedar Point?

Ex. 2 Chris wants to determine the most desired location for the senior class trip. Which questions will get him the answer he is seeking?

a) Do you like Disneyland?

b) Which is better, King’s Island or Cedar Point?

c) Where would you most like to go on the senior trip?

Ex. 2 Chris wants to determine the most desired location for the senior class trip. Which questions will get him the answer he is seeking?

a) Do you like Disneyland?

b) Which is better, King’s Island or Cedar Point?

c) Where would you most like to go on the senior trip?

Option “c” would be the best question to ask. Option “a” only asks about Disneyland and option “b” only asks about King’s Island or Cedar Point. Both are limited and, therefore, biased.

• Observational Study – data are recorded after just observing the sample and used to compare reactions and draw a conclusion about responses of the population.

• Observational Study – data are recorded after just observing the sample and used to compare reactions and draw a conclusion about responses of the population.

• Experiment – data are recorded after changing the sample and used to make general conclusions about what will happen during an event.

• Observational Study – data are recorded after just observing the sample and used to compare reactions and draw a conclusion about responses of the population.

• Experiment – data are recorded after changing the sample and used to make general conclusions about what will happen during an event.

• Treatment Group – the people, animals, or objects given the treatment.

• Observational Study – data are recorded after just observing the sample and used to compare reactions and draw a conclusion about responses of the population.

• Experiment – data are recorded after changing the sample and used to make general conclusions about what will happen during an event.

• Treatment Group – the people, animals, or objects given the treatment.

• Control Group – the people, animals or objects given a placebo, or false treatment.

Ex. 3 State whether each situation represents an observational study or experiment. If it is an experiment, identify the treatment & control groups. Then determine if there is bias.

Ex. 3 State whether each situation represents an observational study or experiment. If it is an experiment, identify the treatment & control groups. Then determine if there is bias.

a) Find 200 students, half of whom participated in extracurricular activities, and compare their grade-point averages.

Ex. 3 State whether each situation represents an observational study or experiment. If it is an experiment, identify the treatment & control groups. Then determine if there is bias.

a) Find 200 students, half of whom participated in extracurricular activities, and compare their grade-point averages.

Observational Study

Ex. 3 State whether each situation represents an observational study or experiment. If it is an experiment, identify the treatment & control groups. Then determine if there is bias.

a) Find 200 students, half of whom participated in extracurricular activities, and compare their grade-point averages.

Observational Study

b) Find 200 people and randomly split them into two groups. One group jogs 2 miles per day and the other group does not jog at all.

Ex. 3 State whether each situation represents an observational study or experiment. If it is an experiment, identify the treatment & control groups. Then determine if there is bias.

a) Find 200 students, half of whom participated in extracurricular activities, and compare their grade-point averages.

Observational Study

b) Find 200 people and randomly split them into two groups. One group jogs 2 miles per day and the other group does not jog at all.

Experiment b/c put into groups and each group has something done to it. The group that jogs is the treatment group and the group that doesn’t jog is the control group.

Ex. 4 Determine whether each situation calls for a survey, an observational study, or and experiment. Explain your reasoning.

Ex. 4 Determine whether each situation calls for a survey, an observational study, or and experiment. Explain your reasoning.

a) You want to test a treatment for a disease.

Ex. 4 Determine whether each situation calls for a survey, an observational study, or and experiment. Explain your reasoning.

a) You want to test a treatment for a disease.Experiment b/c you would need a control

group and a group to receive the treatment.

Ex. 4 Determine whether each situation calls for a survey, an observational study, or and experiment. Explain your reasoning.

a) You want to test a treatment for a disease.Experiment b/c you would need a control

group and a group to receive the treatment.

b) You want to find opinions on a presidential election.

Ex. 4 Determine whether each situation calls for a survey, an observational study, or and experiment. Explain your reasoning.

a) You want to test a treatment for a disease.Experiment b/c you would need a control

group and a group to receive the treatment.

b) You want to find opinions on a presidential election.

Survey b/c you are determining a conclusion of a population.

Ex. 4 Determine whether each situation calls for a survey, an observational study, or and experiment. Explain your reasoning.

a) You want to test a treatment for a disease.Experiment b/c you would need a control group and a

group to receive the treatment.

b) You want to find opinions on a presidential election.Survey b/c you are determining a conclusion of a

population.

c) You want to find out if 10 yrs. of smoking affects lung capacity.

Ex. 4 Determine whether each situation calls for a survey, an observational study, or and experiment. Explain your reasoning.

a) You want to test a treatment for a disease.Experiment b/c you would need a control group and a group

to receive the treatment.

b) You want to find opinions on a presidential election.Survey b/c you are determining a conclusion of a population.

c) You want to find out if 10 yrs. of smoking affects lung capacity.Observational study b/c you would observe the effects on

people’s lung capacity who have smoked for 10 yrs.